Method, apparatus, and medium for video processing

Abstract

Embodiments of the disclosure provide a solution for video processing. A method for video processing is proposed. The method includes: obtaining, for a conversion between a video unit of a video and a bitstream of the video, a first motion information and a second motion information of the video unit; refining the second motion information by using the first motion information, during a motion refinement process of the video unit; and performing the conversion based on the refined first and second motion information.

I/We claim: 
     
         1 . A method of video processing, wherein comprising:
 obtaining, for a conversion between a video unit of a video and a bitstream of the video, a first motion information and a second motion information of the video unit;   refining the second motion information by using the first motion information, during a motion refinement process of the video unit; and   performing the conversion based on the refined first and second motion information.   
     
     
         2 . The method of  claim 1 , wherein the motion refinement process is bilateral matching, or wherein the motion refinement process is template matching. 
     
     
         3 . The method of  claim 1 , wherein the first motion information and the second motion information are in the same reference list, or
 wherein the first motion information and the second motion information are in different reference lists.   
     
     
         4 . The method of  claim 1 , wherein the first motion information or the second motion information is in the same direction, and/or
 wherein picture order counts (POCs) of both the first motion information and the second motion information are less than or larger than that of a current picture.   
     
     
         5 . The method of  claim 1 , wherein the first motion information is refined before being used to refine the second motion information, and/or
 wherein the first motion information or the second motion information is refined more than once.   
     
     
         6 . The method of  claim 1 , wherein an iterative refinement is used. 
     
     
         7 . The method of  claim 6 , wherein an i-th refined motion information of the first motion information is used to obtain a j-th refined motion information of the second motion information, wherein i and j are integer numbers, or
 wherein the j-th refined motion information of the second motion information is used to obtain the i-th refined motion information of the first motion information.   
     
     
         8 . The method of  claim 7 , wherein i is less than j, or
 wherein i is equal to j, or   wherein i is larger than j, and/or   wherein the j-th refined motion information of the second motion information is used to obtain a (i+1)-th refined motion information of the first motion information, after the i-th refined motion information of the first motion information is used to obtain the j-th refined motion information of the second motion information.   
     
     
         9 . The method of  claim 6 , wherein a template size or a template shape during the iterative refinement is different from that without iterative refinement, and/or
 wherein at least one of search range or a pattern shape used for search is different from that without iterative refinement.   
     
     
         10 . The method of  claim 1 , wherein a determination of at least one of: search range or pattern shape used for search in the motion refinement process depends on coding information, and wherein the motion refinement process is template matching. 
     
     
         11 . The method of  claim 10 , wherein the coding information comprises at least one of:
 a precision of motion vector (MV),   a precision MV difference (MVD), or   a syntax element indicating MV or MVD, or   wherein the search range for a first MV precision is larger than that for a second MV precision, or   wherein the number of searching points of the pattern shape for a first MV precision is more than that for a second MV precision.   
     
     
         12 . The method of  claim 1 , wherein at least one adaptive factor is used for a determination of whether uni-prediction or bi-prediction is used. 
     
     
         13 . The method of  claim 12 , wherein a determination of using which factor depends on coding information. 
     
     
         14 . The method of  claim 13 , wherein the coding information comprises POC or POC difference, or wherein the coding information comprises whether two reference pictures are in the same direction. 
     
     
         15 . The method of  claim 1 , wherein a first motion refinement is used as a part of a second motion refinement. 
     
     
         16 . The method of  claim 15 , wherein the first motion refinement is a template matching, and the second motion refinement comprises a bilateral matching, and/or
 wherein the bilateral matching comprises one of:   a decoder side motion vector refinement (DMVR),   a multi-pass DMVR, or   an adaptive DMVR.   
     
     
         17 . The method of  claim 1 , wherein the conversion includes encoding the video unit into the bitstream, or
 wherein the conversion includes decoding the video unit from the bitstream.   
     
     
         18 . An apparatus for video processing comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform acts comprising:
 obtaining, for a conversion between a video unit of a video and a bitstream of the video, a first motion information and a second motion information of the video unit;   refining the second motion information by using the first motion information, during a motion refinement process of the video unit; and   performing the conversion based on the refined first and second motion information.   
     
     
         19 . A non-transitory computer-readable storage medium storing instructions that cause a processor to perform acts comprising:
 obtaining, for a conversion between a video unit of a video and a bitstream of the video, a first motion information and a second motion information of the video unit;   refining the second motion information by using the first motion information, during a motion refinement process of the video unit; and   performing the conversion based on the refined first and second motion information.   
     
     
         20 . A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by an apparatus for video processing, wherein the method comprises:
 obtaining a first motion information and a second motion information of a video unit of the video;   refining the second motion information by using the first motion information, during a motion refinement process of the video unit; and   generating the bitstream based on the refined first and second motion information.